1. Field of the Invention
The present invention relates to the field of electronic and informatics and can be used in the production of color displays for computers and television (TV) sets having a screen area up to one square meter (m), and also for possible information systems in which the screen area considerably exceeds one square meter.
2. Background Art
The development of high-quality, wide-screen, flat panel displays (FPD) which currently account for more than half of the unit's production cost is the major challenge for the emerging high-tech household and industrial markets offering high definition televisions (HDTV), personal computers (PC), and electronic books.
Flat display types currently available include color and black-and-white liquid crystal displays (LCD) and wide screen color plasma display panels (PDP). LCDs, however, are relatively small, highly dependent on the angle of observation, and hard to operate. PDPs, in turn, consume much energy per unit of space, have intricate matrix high-voltage electronic controls, and emit high levels of electromagnetic radiation. Both displays are prohibitively expensive and cannot so far be produced on a regular basis to supplant the cathode ray tube (CRT).
Competing technologies such as field emission displays (FED), electro-luminescent displays (ELD), and light-emitting diodes (LED) have yet to be commercially available [1].
Recent hopes are tied to using polymer materials for flat panel displays. Organic materials such as PPV, DPVBi, etc., are considered good for producing low-cost, flexible plastic light-diode large-size panels. A great amount of effort is being made to develop polymer-based LCDs. None of these are commercially available, however.
Recent years have seen, besides the above technologies, a brand new one based on electronic clusters (EC) as disclosed in U.S. Pat. No. 5,018,180 issued to K. R. Shoulders [2]. A good case in point here is a newly developed matrix-controlled 2000*2000 PGB pixel resolution display. This technology eliminates the weaknesses of FED and PDP and achieves a high electric-to-light energy conversion ratio within an area of about one square meter wide and one cm thick.
The intermediate size displays can be carried out on the basis of magnetic or electrostatic balls in which one hemisphere is painted. They are usually apply for the creation of the static image, so-called electronic paper (EP).
The spherical particles have two areas: reflecting and black. These balls turn in a magnetic or electrostatic field created by two conductors with matrix x-y addressing. The degree of the turn of the balls defines the grey scale. After field removal, the balls keep the last orientation for an indefinite period of time. The time of turning on is about 30 ms. It is supposed that the power of dispersion is small. The technology can appear rather perspective for the creation of electronic magazines in the future. But it is not very promising in making PCs and TVs because of a matrix control system of rotation and low speed.
The display types available are either light-emitting or external light controlling. The latter are divided into light-reflecting, light-transparent, and light-absorbing.
An important problem of fatigue contributor to reconfiguration with is display flickering with the standard 50/60 Hz frame rotation frequency. Invisible to the eye, it synchronizes the α-rhythms of the human brain making the latter behave unnaturally. This in its turn tires the user dramatically. The situation can be avoided by increasing the display operation and respectively bringing the frame rotation frequency up to 75 Hz or more [1].
One should also take into account the user's fatigue resulting from the display's electromagnetic radiation. Moreover, prolonged exposure may affect general health.
Ways of image formation, or addressing, have a direct influence on the display's specifications. The two main approaches are based on either a movable radiation source (a driver) or an immovable radiation source. In the former case, radiation is generated by a limited number of drivers (one to three) providing for successive frame rotation along x-y coordinates out of z coordinate perpendicular to them, like in CRT.
In the latter case, the sources of radiation are created by an orthogonal matrix right in the electrode crossings along x-y coordinates and scanned by way of appropriate switching of numerous control buses. Here, the amount of control buses is proportional to the square root of the number of image scanning points, i.e., about 2,000 or more.
There is also a combined rotation version, with the driver moving along the display surface with the assistance of a few special control electrodes. This approach to addressing is the most efficient from the control point of view. However, it is good for image creation only in special plasma displays through self-scanning (SS) of the gas discharge along the lines. This eliminates the need to use numerous high-voltage controls along x-y element buses, making the whole setup easier to manage and reducing power consumption and electromagnetic radiation from the display.
The combined version, despite its advantages, has so far failed to work for other types of displays.
From the analysis follows that development of cheap, large-size flat displays with low level of electromagnetic fields and high frame rotation frequency continues to be rather urgent.